A tumultuous week ended with a bombshell that is sure to ratchet up the anger and tension surrounding the shooting death of teenager Trayvon Martin.

A series of 911 calls from the last moments of Trayvon's life were supposed to shed light on why police have not arrested the shooter, crime-watch volunteer George Zimmerman. Instead, they have fueled even more rage — not just in Central Florida, but across the country.

Trayvon's family and supporters vow they won't give up until Zimmerman is charged with the 17-year-old's slaying late last month.

At the heart of this maelstrom — in which the thorny issues of race and justice have surfaced as themes — is a boy who dreamed of becoming a pilot and liked to work with his hands.

After taking an airplane ride two years ago, Trayvon decided he wanted to learn to fly, his uncle Ronald Fulton said. The teen attended a Miami aviation school part time and was studying to be an engineer, a path to realizing his ambition, Fulton said.

Math was Trayvon's favorite subject.

He liked to tinker, and he was good with his hands. He once took apart and repaired a broken scooter, Fulton said, and he liked to construct model cars and airplanes and draw pictures of things he wanted to build.

"He was extremely creative," said Michelle Kypriss, Trayvon's English teacher at Dr. Michael M. Krop Senior High School in Miami. "He just loved building things. He really was intrigued by how things worked."

She described Trayvon, a junior, as an A and B student who majored in cheerfulness.

His uncle said Trayvon was still a typical kid who loved sports, music and was just feeling the first flush of youth. "He was trying to start driving. He was just finding out about girls."

Trayvon was close to his 21-year-old brother Jahvaris, also of Miami, and assisted his uncle, a quadriplegic, on outings to University of Miami basketball games.

"He used to help me," Fulton said, voice breaking.

Trayvon — who was known as "Tray" or "Slimm" — played youth football during his early teens and helped his father coach Little League baseball, said Fulton, whose sister, Sybrina Fulton, is Trayvon's mother.

Trayvon was under a five-day suspension when he was shot that Sunday night, but Kypriss said it was due to tardiness and not misbehavior.

"Trayvon was not a violent or dangerous child. He was not known for misbehaving," the teacher said. "He was suspended because he was late too many times."

Grief counselors were at the school for several days after Trayvon's death. Kypriss expects students to remember their missing classmate when they return from spring break Monday.

A reported 1,000 people, including his classmates, attended the teen's March 3 funeral in Miami.

"I don't think he'll ever be forgotten," Fulton said. "As long as I live, as long as everybody that came into contact with him lives, Trayvon will live."

'Up to no good'

Police said they hoped releasing the 911 calls surrounding the altercation and shooting would help clarify why they didn't arrest Zimmerman.

But in a call to the Police Department's non-emergency line, Zimmerman can be heard pursuing the boy, even after dispatchers tell him not to. He describes Trayvon as a black male who looked like he was "up to no good."

He begins the call by saying there's been a rash of break-ins in the neighborhood. At one point in the call, Zimmerman says: "These assholes, they always get away."

In the 911 calls, neighbors described an altercation between the two men. On one call, screams can be heard, and then at least one gunshot.

After the recordings were released Friday night, Twitter exploded with thousands of emotional responses, comments and even threats.

Many of the messages shared similar sentiments:

•"My 15 y/o, 5'9" son left home tonite wearing a hoodie. Who might think him threatening enuf that he shouldn't make it home? #Trayvon."

•"#TrayvonMartin is the reminder we need to fight for justice and equity. All our brown sons remain at risk."

Shooter wanted to be cop

George Zimmerman wanted to be a police officer, and sometimes his aspirations led to action.

When he saw a 24-year-old Lake Mary man shoplift a 24-inch TV from an Albertsons supermarket in 2003, he called the Seminole County Sheriff's Office and followed the suspect's car for several blocks, allowing a deputy to make an arrest, records show.

The next year, Zimmerman followed a man who allegedly spit at him while driving, according to an incident report. The other driver accused Zimmerman — whom he described as "irate" — of tailgating, and was not arrested.

Though there are no enrollment records suggesting Zimmerman has attended a law-enforcement academy, he carried a concealed weapon and expressed his desire to wear a badge. He's currently enrolled in a general education program at Seminole State College.

"I hold law enforcement officers in the highest regard as I hope to one day become one," Zimmerman wrote in a 2008 application to theSeminole County Sheriff's Officecitizen's law enforcement academy, a class that teaches citizens about policing and how the Sheriff's Office works.

Zimmerman was arrested in 2005 at a bar near the University of Central Florida on charges of assault on a law-enforcement officer and resisting arrest with violence. Both charges were ultimately dropped, according to court records.

In the weeks since the shooting, Zimmerman has moved out of his home and his parents have temporarily relocated. They've received death threats, his father, Robert Zimmerman, told the Orlando Sentinel.

The elder Zimmerman insists his son is not racist, although the shooting was widely characterized as a black teen shot by a white man. Zimmerman is Hispanic and speaks Spanish, his father said.

Robert Zimmerman maintains that his son was not the aggressor in his confrontation with Trayvon.

Records show George Zimmerman was no stranger to Sanford police or the officers who patrol his neighborhood.

He contacted police 46 times in the past 15 months, the agency reported. Many of the calls appear related to his crime-watch volunteer role. The most frequent reason for his calls — nine times — was to report a suspicious person, the agency said.

That's what he called to report when he saw Trayvon Martin walking through the neighborhood in a hooded sweat shirt late last month.

A bag of Skittles

Trayvon took his last breath in a bed of damp grass just feet from the safety of a relative's home a few minutes before theNBA All-Star Gamewas set to tip off in Orlando.

The teen from Miami had been returning from a nearby 7-Eleven, where he bought a can of iced tea and a bag of Skittles, when he was spotted by Zimmerman.

What happened next is in dispute, but in the end Trayvon died from a single gunshot wound to his chest.

Trayvon's story has spread across social networking sites Facebook and Twitter. An online petition calling for the arrest and prosecution of Zimmerman has collected more than 250,000 signatures on Change.org.

That's the power of social media, said Deanna Zandt, a Brooklyn-based consultant and author.

Similar online campaigns recently caused some advertisers to abandon conservative talk-radio host Rush Limbaugh after he made controversial comments about women and birth control. The Susan G. Komen for the Cure foundation reversed its decision to pull funding from Planned Parenthood in response to an uproar on the web.

"Now people have a chance to say, 'This is what actually matters to me,'" Zandt said. "I don't have to rely on a mainstream news station to determine what matters."

Trayvon is young, like the students at Chico State University in California who held a silent demonstration Thursday to protest his killing.

He is black, like Corey Chisholm of Springfield, Pa., who learned about the shooting on a social-media network.

"It's appalling that something like this can go unjustified," Chisholm, 33, said. "If the roles were reversed would anyone walk away from this?"

SANFORD — The handgun that killed Trayvon Martin, an unarmed black 17-year-old, was fired once — not twice — by a neighborhood crime watch volunteer, according to information obtained by the Orlando Sentinel.